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Apple: Refactor deployment target version parsing
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- Merge minimum OS version list into one function (makes it easier to
  see the logic in it).
- Parse patch deployment target versions.
- Consistently specify deployment target in LLVM target (previously
  omitted on `aarch64-apple-watchos`).
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@madsmtm
madsmtm committed Sep 5, 2024
1 parent 23cdb50 commit 5b51331
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Showing 28 changed files with 322 additions and 363 deletions.
33 changes: 24 additions & 9 deletions compiler/rustc_codegen_ssa/src/back/metadata.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -372,27 +372,42 @@ pub(crate) fn create_object_file(sess: &Session) -> Option<write::Object<'static
Some(file)
}

/// Since Xcode 15 Apple's LD requires object files to contain information about what they were
/// built for (LC_BUILD_VERSION): the platform (macOS/watchOS etc), minimum OS version, and SDK
/// version. This returns a `MachOBuildVersion` for the target.
/// Mach-O files contain information about:
/// - The platform/OS they were built for (macOS/watchOS/Mac Catalyst/iOS simulator etc).
/// - The minimum OS version / deployment target.
/// - The version of the SDK they were targetting.
///
/// In the past, this was accomplished using the LC_VERSION_MIN_MACOSX, LC_VERSION_MIN_IPHONEOS,
/// LC_VERSION_MIN_TVOS or LC_VERSION_MIN_WATCHOS load commands, which each contain information
/// about the deployment target and SDK version, and implicitly, by their presence, which OS they
/// target. Simulator targets were determined if the architecture was x86_64, but there was e.g. a
/// LC_VERSION_MIN_IPHONEOS present.
///
/// This is of course brittle and limited, so modern tooling emit the LC_BUILD_VERSION load
/// command (which contains all three pieces of information in one) when the deployment target is
/// high enough, or the target is something that wouldn't be encodable with the old load commands
/// (such as Mac Catalyst, or Aarch64 iOS simulator).
///
/// Since Xcode 15, Apple's LD apparently requires object files to use this load command, so this
/// returns the `MachOBuildVersion` for the target to do so.
fn macho_object_build_version_for_target(target: &Target) -> object::write::MachOBuildVersion {
/// The `object` crate demands "X.Y.Z encoded in nibbles as xxxx.yy.zz"
/// e.g. minOS 14.0 = 0x000E0000, or SDK 16.2 = 0x00100200
fn pack_version((major, minor): (u32, u32)) -> u32 {
(major << 16) | (minor << 8)
fn pack_version((major, minor, patch): (u16, u8, u8)) -> u32 {
let (major, minor, patch) = (major as u32, minor as u32, patch as u32);
(major << 16) | (minor << 8) | patch
}

let platform =
rustc_target::spec::current_apple_platform(target).expect("unknown Apple target OS");
let min_os = rustc_target::spec::current_apple_deployment_target(target)
.expect("unknown Apple target OS");
let sdk =
let min_os = rustc_target::spec::current_apple_deployment_target(target);
let (sdk_major, sdk_minor) =
rustc_target::spec::current_apple_sdk_version(platform).expect("unknown Apple target OS");

let mut build_version = object::write::MachOBuildVersion::default();
build_version.platform = platform;
build_version.minos = pack_version(min_os);
build_version.sdk = pack_version(sdk);
build_version.sdk = pack_version((sdk_major, sdk_minor, 0));
build_version
}

Expand Down
6 changes: 3 additions & 3 deletions compiler/rustc_driver_impl/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -871,9 +871,9 @@ fn print_crate_info(
use rustc_target::spec::current_apple_deployment_target;

if sess.target.is_like_osx {
let (major, minor) = current_apple_deployment_target(&sess.target)
.expect("unknown Apple target OS");
println_info!("deployment_target={}", format!("{major}.{minor}"))
let (major, minor, patch) = current_apple_deployment_target(&sess.target);
let patch = if patch != 0 { format!(".{patch}") } else { String::new() };
println_info!("deployment_target={major}.{minor}{patch}")
} else {
#[allow(rustc::diagnostic_outside_of_impl)]
sess.dcx().fatal("only Apple targets currently support deployment version info")
Expand Down
262 changes: 125 additions & 137 deletions compiler/rustc_target/src/spec/base/apple/mod.rs
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
use std::borrow::Cow;
use std::env;
use std::num::ParseIntError;

use crate::spec::{
add_link_args, add_link_args_iter, cvs, Cc, DebuginfoKind, FramePointer, LinkArgs,
Expand Down Expand Up @@ -123,15 +124,8 @@ fn pre_link_args(os: &'static str, arch: Arch, abi: TargetAbi) -> LinkArgs {
};

let min_version: StaticCow<str> = {
let (major, minor) = match os {
"ios" => ios_deployment_target(arch, abi.target_abi()),
"tvos" => tvos_deployment_target(),
"watchos" => watchos_deployment_target(),
"visionos" => visionos_deployment_target(),
"macos" => macos_deployment_target(arch),
_ => unreachable!(),
};
format!("{major}.{minor}").into()
let (major, minor, patch) = deployment_target(os, arch, abi);
format!("{major}.{minor}.{patch}").into()
};
let sdk_version = min_version.clone();

Expand Down Expand Up @@ -163,15 +157,22 @@ fn pre_link_args(os: &'static str, arch: Arch, abi: TargetAbi) -> LinkArgs {
add_link_args_iter(
&mut args,
LinkerFlavor::Darwin(Cc::Yes, Lld::No),
["-target".into(), mac_catalyst_llvm_target(arch).into()].into_iter(),
["-target".into(), llvm_target(os, arch, abi)].into_iter(),
);
}

args
}

pub(crate) fn opts(os: &'static str, arch: Arch, abi: TargetAbi) -> TargetOptions {
TargetOptions {
/// Get the base target options, LLVM target and `target_arch` from the three
/// things that uniquely identify Rust's Apple targets: The OS, the
/// architecture, and the ABI.
pub(crate) fn base(
os: &'static str,
arch: Arch,
abi: TargetAbi,
) -> (TargetOptions, StaticCow<str>, StaticCow<str>) {
let opts = TargetOptions {
abi: abi.target_abi().into(),
os: os.into(),
cpu: arch.target_cpu(abi).into(),
Expand Down Expand Up @@ -221,10 +222,11 @@ pub(crate) fn opts(os: &'static str, arch: Arch, abi: TargetAbi) -> TargetOption
link_env: Cow::Borrowed(&[(Cow::Borrowed("ZERO_AR_DATE"), Cow::Borrowed("1"))]),

..Default::default()
}
};
(opts, llvm_target(os, arch, abi), arch.target_arch())
}

pub fn sdk_version(platform: u32) -> Option<(u32, u32)> {
pub fn sdk_version(platform: u32) -> Option<(u16, u8)> {
// NOTE: These values are from an arbitrary point in time but shouldn't make it into the final
// binary since the final link command will have the current SDK version passed to it.
match platform {
Expand Down Expand Up @@ -258,58 +260,108 @@ pub fn platform(target: &Target) -> Option<u32> {
})
}

pub fn deployment_target(target: &Target) -> Option<(u32, u32)> {
let (major, minor) = match &*target.os {
"macos" => {
// This does not need to be specific. It just needs to handle x86 vs M1.
let arch = match target.arch.as_ref() {
"x86" | "x86_64" => X86_64,
"arm64e" => Arm64e,
_ => Arm64,
};
macos_deployment_target(arch)
}
"ios" => {
let arch = match target.arch.as_ref() {
"arm64e" => Arm64e,
_ => Arm64,
};
ios_deployment_target(arch, &target.abi)
}
"watchos" => watchos_deployment_target(),
"tvos" => tvos_deployment_target(),
"visionos" => visionos_deployment_target(),
_ => return None,
/// Hack for calling `deployment_target` outside of this module.
pub fn deployment_target_for_target(target: &Target) -> (u16, u8, u8) {
let arch = if target.llvm_target.starts_with("arm64e") {
Arch::Arm64e
} else if target.arch == "aarch64" {
Arch::Arm64
} else {
// Dummy architecture, only used by `deployment_target` anyhow
Arch::X86_64
};

Some((major, minor))
let abi = match &*target.abi {
"macabi" => TargetAbi::MacCatalyst,
"sim" => TargetAbi::Simulator,
"" => TargetAbi::Normal,
abi => unreachable!("invalid abi '{abi}' for Apple target"),
};
deployment_target(&target.os, arch, abi)
}

fn from_set_deployment_target(var_name: &str) -> Option<(u32, u32)> {
let deployment_target = env::var(var_name).ok()?;
let (unparsed_major, unparsed_minor) = deployment_target.split_once('.')?;
let (major, minor) = (unparsed_major.parse().ok()?, unparsed_minor.parse().ok()?);
/// Get the deployment target based on the standard environment variables, or
/// fall back to a sane default.
fn deployment_target(os: &str, arch: Arch, abi: TargetAbi) -> (u16, u8, u8) {
// When bumping a version in here, remember to update the platform-support
// docs too.
//
// NOTE: If you are looking for the default deployment target, prefer
// `rustc --print deployment-target`, as the default here may change in
// future `rustc` versions.

// Minimum operating system versions currently supported by `rustc`.
let os_min = match os {
"macos" => (10, 12, 0),
"ios" => (10, 0, 0),
"tvos" => (10, 0, 0),
"watchos" => (5, 0, 0),
"visionos" => (1, 0, 0),
_ => unreachable!("tried to get deployment target for non-Apple platform"),
};

Some((major, minor))
}
// On certain targets it makes sense to raise the minimum OS version.
let min = match (os, arch, abi) {
// Use 11.0 on Aarch64 as that's the earliest version with M1 support.
("macos", Arch::Arm64 | Arch::Arm64e, _) => (11, 0, 0),
("ios", Arch::Arm64e, _) => (14, 0, 0),
// Mac Catalyst defaults to 13.1 in Clang.
("ios", _, TargetAbi::MacCatalyst) => (13, 1, 0),
_ => os_min,
};

fn macos_default_deployment_target(arch: Arch) -> (u32, u32) {
match arch {
Arm64 | Arm64e => (11, 0),
_ => (10, 12),
}
}
// The environment variable used to fetch the deployment target.
let env_var = match os {
"macos" => "MACOSX_DEPLOYMENT_TARGET",
"ios" => "IPHONEOS_DEPLOYMENT_TARGET",
"watchos" => "WATCHOS_DEPLOYMENT_TARGET",
"tvos" => "TVOS_DEPLOYMENT_TARGET",
"visionos" => "XROS_DEPLOYMENT_TARGET",
_ => unreachable!("tried to get deployment target env var for non-Apple platform"),
};

fn macos_deployment_target(arch: Arch) -> (u32, u32) {
// If you are looking for the default deployment target, prefer `rustc --print deployment-target`.
// Note: If bumping this version, remember to update it in the rustc/platform-support docs.
from_set_deployment_target("MACOSX_DEPLOYMENT_TARGET")
.unwrap_or_else(|| macos_default_deployment_target(arch))
if let Ok(deployment_target) = env::var(env_var) {
match parse_version(&deployment_target) {
// It is common that the deployment target is set too low, e.g. on
// macOS Aarch64 to also target older x86_64, the user may set a
// lower deployment target than supported.
//
// To avoid such issues, we silently raise the deployment target
// here.
// FIXME: We want to show a warning when `version < os_min`.
Ok(version) => version.max(min),
// FIXME: Report erroneous environment variable to user.
Err(_) => min,
}
} else {
min
}
}

pub(crate) fn macos_llvm_target(arch: Arch) -> String {
let (major, minor) = macos_deployment_target(arch);
format!("{}-apple-macosx{}.{}.0", arch.target_name(), major, minor)
/// Generate the target triple that we need to pass to LLVM and/or Clang.
fn llvm_target(os: &str, arch: Arch, abi: TargetAbi) -> StaticCow<str> {
// The target triple depends on the deployment target, and is required to
// enable features such as cross-language LTO, and for picking the right
// Mach-O commands.
//
// Certain optimizations also depend on the deployment target.
let (major, minor, patch) = deployment_target(os, arch, abi);
let arch = arch.target_name();
// Convert to the "canonical" OS name used by LLVM:
// https://github.com/llvm/llvm-project/blob/llvmorg-18.1.8/llvm/lib/TargetParser/Triple.cpp#L236-L282
let os = match os {
"macos" => "macosx",
"ios" => "ios",
"watchos" => "watchos",
"tvos" => "tvos",
"visionos" => "xros",
_ => unreachable!("tried to get LLVM target OS for non-Apple platform"),
};
let environment = match abi {
TargetAbi::Normal => "",
TargetAbi::MacCatalyst => "-macabi",
TargetAbi::Simulator => "-simulator",
};
format!("{arch}-apple-{os}{major}.{minor}.{patch}{environment}").into()
}

fn link_env_remove(os: &'static str) -> StaticCow<[StaticCow<str>]> {
Expand Down Expand Up @@ -349,83 +401,19 @@ fn link_env_remove(os: &'static str) -> StaticCow<[StaticCow<str>]> {
}
}

fn ios_deployment_target(arch: Arch, abi: &str) -> (u32, u32) {
// If you are looking for the default deployment target, prefer `rustc --print deployment-target`.
// Note: If bumping this version, remember to update it in the rustc/platform-support docs.
let (major, minor) = match (arch, abi) {
(Arm64e, _) => (14, 0),
// Mac Catalyst defaults to 13.1 in Clang.
(_, "macabi") => (13, 1),
_ => (10, 0),
};
from_set_deployment_target("IPHONEOS_DEPLOYMENT_TARGET").unwrap_or((major, minor))
}

pub(crate) fn ios_llvm_target(arch: Arch) -> String {
// Modern iOS tooling extracts information about deployment target
// from LC_BUILD_VERSION. This load command will only be emitted when
// we build with a version specific `llvm_target`, with the version
// set high enough. Luckily one LC_BUILD_VERSION is enough, for Xcode
// to pick it up (since std and core are still built with the fallback
// of version 7.0 and hence emit the old LC_IPHONE_MIN_VERSION).
let (major, minor) = ios_deployment_target(arch, "");
format!("{}-apple-ios{}.{}.0", arch.target_name(), major, minor)
}

pub(crate) fn mac_catalyst_llvm_target(arch: Arch) -> String {
let (major, minor) = ios_deployment_target(arch, "macabi");
format!("{}-apple-ios{}.{}.0-macabi", arch.target_name(), major, minor)
}

pub(crate) fn ios_sim_llvm_target(arch: Arch) -> String {
let (major, minor) = ios_deployment_target(arch, "sim");
format!("{}-apple-ios{}.{}.0-simulator", arch.target_name(), major, minor)
}

fn tvos_deployment_target() -> (u32, u32) {
// If you are looking for the default deployment target, prefer `rustc --print deployment-target`.
// Note: If bumping this version, remember to update it in the rustc platform-support docs.
from_set_deployment_target("TVOS_DEPLOYMENT_TARGET").unwrap_or((10, 0))
}

pub(crate) fn tvos_llvm_target(arch: Arch) -> String {
let (major, minor) = tvos_deployment_target();
format!("{}-apple-tvos{}.{}.0", arch.target_name(), major, minor)
}

pub(crate) fn tvos_sim_llvm_target(arch: Arch) -> String {
let (major, minor) = tvos_deployment_target();
format!("{}-apple-tvos{}.{}.0-simulator", arch.target_name(), major, minor)
}

fn watchos_deployment_target() -> (u32, u32) {
// If you are looking for the default deployment target, prefer `rustc --print deployment-target`.
// Note: If bumping this version, remember to update it in the rustc platform-support docs.
from_set_deployment_target("WATCHOS_DEPLOYMENT_TARGET").unwrap_or((5, 0))
}

pub(crate) fn watchos_llvm_target(arch: Arch) -> String {
let (major, minor) = watchos_deployment_target();
format!("{}-apple-watchos{}.{}.0", arch.target_name(), major, minor)
}

pub(crate) fn watchos_sim_llvm_target(arch: Arch) -> String {
let (major, minor) = watchos_deployment_target();
format!("{}-apple-watchos{}.{}.0-simulator", arch.target_name(), major, minor)
}

fn visionos_deployment_target() -> (u32, u32) {
// If you are looking for the default deployment target, prefer `rustc --print deployment-target`.
// Note: If bumping this version, remember to update it in the rustc platform-support docs.
from_set_deployment_target("XROS_DEPLOYMENT_TARGET").unwrap_or((1, 0))
}

pub(crate) fn visionos_llvm_target(arch: Arch) -> String {
let (major, minor) = visionos_deployment_target();
format!("{}-apple-visionos{}.{}.0", arch.target_name(), major, minor)
}

pub(crate) fn visionos_sim_llvm_target(arch: Arch) -> String {
let (major, minor) = visionos_deployment_target();
format!("{}-apple-visionos{}.{}.0-simulator", arch.target_name(), major, minor)
/// Parse an OS version triple (SDK version or deployment target).
///
/// The size of the returned numbers here are limited by Mach-O's
/// `LC_BUILD_VERSION`.
fn parse_version(version: &str) -> Result<(u16, u8, u8), ParseIntError> {
if let Some((major, minor)) = version.split_once('.') {
let major = major.parse()?;
if let Some((minor, patch)) = minor.split_once('.') {
Ok((major, minor.parse()?, patch.parse()?))
} else {
Ok((major, minor.parse()?, 0))
}
} else {
Ok((version.parse()?, 0, 0))
}
}
9 changes: 9 additions & 0 deletions compiler/rustc_target/src/spec/base/apple/tests.rs
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Original file line number Diff line number Diff line change
@@ -1,3 +1,4 @@
use super::parse_version;
use crate::spec::targets::{
aarch64_apple_darwin, aarch64_apple_ios_sim, aarch64_apple_visionos_sim,
aarch64_apple_watchos_sim, i686_apple_darwin, x86_64_apple_darwin, x86_64_apple_ios,
Expand Down Expand Up @@ -42,3 +43,11 @@ fn macos_link_environment_unmodified() {
);
}
}

#[test]
fn test_parse_version() {
assert_eq!(parse_version("10"), Ok((10, 0, 0)));
assert_eq!(parse_version("10.12"), Ok((10, 12, 0)));
assert_eq!(parse_version("10.12.6"), Ok((10, 12, 6)));
assert_eq!(parse_version("9999.99.99"), Ok((9999, 99, 99)));
}
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